用于通信漏缆故障定位的脉冲压缩理论算法研究

In recent years, the leaky coaxial cable wireless communication, widely applied in the circumstances of half-closed or closed space domain, such as subway, tunnel, mine and high-speed railway, is the most advanced wireless communication technology. The performance of leaky cable plays a very important role in mobile communication network. However, there have been no relevant solutions for the fault detection and location of leaky cable at home and abroad. Therefore, this subject makes a deep research on the theory of fault location and detection for leaky cable. In this subject, the transmission characteristics and channel noise characteristics of leaky cable will be classified and modeled. Similar to the active radar working principle, the fault location of leaky cable will be studied by the pulse compression technology. Taking the linear frequency modulation, nonlinear frequency modulated signal as the main research object, the modulation mode identification, detection and parameter estimation in intra-pulse of the pulse compression signal will be studied, respectively. The system model of fault detection of pulse compression will be established. Comparing the linear frequency modulation (LFM), nonlinear frequency modulation (NLFM), and phase coded of pulse compression signal modulation method, their filter algorithms will be studied respectively. The research of this subject will contribute important academic value to rich theoretical system of leaky cable fault location, which will have significance to improve the reliability of mine wireless communication.

近些年来，漏泄同轴电缆无线通信是最为先进的一种无线通信技术，广泛应用于地铁、隧道、矿井及高速铁路沿线等半闭域或闭域空间的移动通信。漏缆的性能对移动通信网络至关重要，但是对于漏缆的故障检测和定位，国内外一直没有相关解决方案，因此本课题对漏缆故障检测定位理论进行深入的研究。基于漏缆中信号的传输特性和信道噪声特性，建立了漏缆信号的传输模型；借鉴主动雷达工作原理，采用脉冲压缩技术对漏缆故障点进行定位研究；以线性调频、非线性调频和相位编码的脉冲压缩方法为研究对象，分别对其脉压信号的脉内调制方式识别、检测和参数估计进行研究，建立脉冲压缩故障定位的系统模型；对比线性调频、非线性调频、相位编码三种脉冲压缩信号的调制方法，并分别研究其匹配滤波器的算法。课题的研究对丰富漏缆故障定位的理论体系具有重要的学术价值，对有效提高矿井无线通信的可靠性具有重要意义。

在煤矿井下、铁路隧道、地铁等封闭或半封闭空间的无线通信中，漏缆故障检测和定位问题普遍存在，其中较为重要的有漏缆衰减模型、信号传输特性、脉冲压缩技术、旁瓣抑制、到达时间估计等，国内外对这类问题的研究十分重视。我们针对这些漏缆故障检测和定位问题进行了深入研究。首先，我们研究了漏缆的传输衰减模型、漏缆中信号的传输规律和波速特性等理论问题，获得了一些列研究成果。然后，在上述研究成果的基础上，提出利用线性调频脉冲压缩方法对漏缆进行检测和故障定位，分析了漏缆常见故障及原因、常见故障类型诊断，阐述了线性调频脉冲压缩故障定位的系统组成及原理；对线性调频信号的时域波形和频谱特性、回波信号去噪算法、匹配滤波的实现、旁瓣抑制方法进行了理论问题，对小波阈值去噪算法进行了优化改进，获得了良好的去噪效果；结合矩形窗主瓣宽度最窄和汉明窗旁瓣高度最低的优点，提出混合卷积窗函数对回波信号进行旁瓣抑制，可以大大提高故障定位的准确率，获得了一系列研究成果。最后对脉压信号的到达时间估计算法进行了研究，提出了基于能量检测和小波变换的到达时间估计算法，分析了克拉美罗限的基本模型，推导到达时间的克拉美罗限，完成对漏缆的故障定位并提高了定位精度。对丰富漏缆故障检测和定位的理论体系具有重要的学术价值，对提高无线通信的可靠性具有重要意义。